1. Field of the Disclosure
The disclosure relates to a mold insert for a molded part mold, more specifically a foam mold or galvano-mold, with an upper part and a matching lower part, with a cavity, more specifically a hollow, wherein the molded part mold impresses a shape onto a material, more specifically a foam, that is introduced into the cavity. The disclosure furthermore relates to a method for manufacturing a molded part and to a molded part.
2. Discussion of the Background Art
In order to manufacture molded foam parts from foam systems, such as soft, semi-hard, hard and integral foam, foaming molds are typically used, which are manufactured from different base materials, depending on the intended use and required output or service life. Plastic material, plastic casting resins or plastic plates are used for instance for prototype or pre-series molds, whereas molds made of aluminum and/or steel are used for production runs, respectively for production of great quantities and complex parts.
These molds mostly consist of a lower shell and an upper shell which are connected by lateral hinges. When closed, both “halves” form a desired hollow space which is also called a cavity and which forms the required molded part.
Slides and inserts or the like, which are inserted and actuated manually, semi automatically and automatically, are used for demolding “undercuts”, ribs and the like. When the mold is open and/or closed, a prepared foam system is introduced into the cavity by means of a gating system via a mixing head.
A negative or undesirable property of the aforementioned systems is that the foam adheres to the aluminum or steel of the foaming molds and can often only be removed mechanically.
In order not to damage the parts during demolding, respectively to be able to remove them intact, diverse release agents are used. These release agents prevent an “adhesion” of the foam parts to the surface of the molds. Wax-based release agents, which are liquefied by means of solvents in order to be applied with a spray pistol or a brush, are mostly used.
These release agents must be applied before each cycle. In doing so the solvent evaporates and the wax leaves a relatively thin layer on the surface of the mold.
This is an independent process which must be stable in order to ensure an unchanging quality of the parts. The release agents are usually applied manually at the foaming plant by a worker by means of a spray pistol and the produced spray and release agent vapors must be aspirated.
Due to the repeated addition of the release layer, a thickening wax layer forms more specifically on the smaller radiuses or on the ribs, which must be regularly removed.
The application of the release layer as well as the regular removal of the wax residue represents a great time and cost expenditure, associated with a repeated interruption of the production process.
A thin release layer also remains on the foam parts themselves. This layer is only unproblematic when the part does not have to be processed any further, i.e. when it is a finished part.
However, should the foam parts be subsequently laminated, this layer of release agent residue makes it more difficult to glue the laminating material onto the foam. The lamination is carried out for instance with a leather or a foil. Thus, the foam part must be cleaned before lamination.
The described release agents are also used in the manufacture of spray skin or deep-drawn foil. So-called galvano-molds are frequently used for manufacturing spray skins and deep-drawn foils. Surfaces for door coverings, instrument panels or center consoles for instance are manufactured by means of these galvano-molds.
Two-part polyurethane systems for instance are sprayed onto these galvano-molds. A skin is thereby formed, the thickness of which varies depending on the applied quantity and which is removed from the mold after a corresponding reaction time. As explained above, release agents, which are applied either manually or automatically, must be used in order to be able to demold or remove the produced skin.
The spray skins thus manufactured are frequently underfoamed with a support resulting in more complex components. To this end, it is also necessary to ensure that the spray skin is freed of any release agents.
Another disadvantage is that galvano-molds are very expensive to manufacture. Amongst other reasons, this is due to the fact that these molds are frequently impressed with a surface grain, which is supposed to impress the skin to be manufactured with a leather-type surface grain for instance. Even the slightest touch by a worker may destroy such a galvano-mold.
Molded foam parts are furthermore frequently covered in so-called coatings. Such a coating is a protection layer. Without this protection layer, the surfaces of molded foam parts tend to pale and to become brittle when exposed to UV-light. The protection layer prevents the exposure to UV-light for instance by absorbing the UV-light.
Coatings can be varnishes for instance, which are added to foam molds before the foaming processes and subsequently homogeneously bond with the foam. After demolding, the foam is then practically covered with the “coat”. The reject rate with molded foam parts covered in coating is relatively high and can amount to up to 30%. For a clean demolding, release agents must also be used.
In the manufacture of carpets, such as are used for instance in vehicle construction, the back side of the carpet—mostly a thermally preformed carpet—is provided with a relatively thin-walled foam layer. The aim of this measure is to increase foot comfort, to absorb tolerances, to prevent fraying and to achieve sound insulation. In order to be able to remove this extensive foam skin from the tool after the reaction time, a thin-walled foil, which has been thermoformed beforehand, is usually placed on the corresponding tool side as a release medium and disposed of after stripping. This process is costly in terms of labor and costs.
The object of the disclosure is to improve the prior art.